300 HPDI Service Items

[jklevin2000]

Good Morning,

I just bought a 32 Regulator with a pair of 2004 300 HPDIs. I know these motors have had issues, but it seems as though a lot of issues were caused by excess carbon, and some other lack of maintenance issues. The port has about 400 hours and the starboard has about 100 hours (new power head in 09). So far I've come up with the following service items, can you HPDI experts chime in and let me know if I'm missing anything.

Spark Plugs
In-Line Fuel Filter
VST Filters
Lower Unit Oil
Water Pump
Thermostats
Oil Filter in the reservoir tank

I've seen a thread about changing the oil in the high pressure pump, is there a service interval for that? Is there anything else specific to these motors I should be aware of? Also, is there any risk by doing the shock treatment of Ring Free?

Thanks in advance,

Kent

[rodbolt17]

and check the engine PID's against the HPDI 3.3L oiling tech bullitens to insure the correct oil pumps are on them.
yes there is a service intravel on the HP pump oil as well as the engine oil tank water trap and alarm testing and the HP belt tensioner.
you may also wish to clean/inspect the water pressure control valve grommets as well.
medium pressure inline filter,the one between the VST and HP pump needs yearly changing.
DO NOT, let me repeat,DO NOT use a standard hose clamp nor standard automotive fuel lines to replace it.
you must use the oeticker clamp,or its equivalent, to replace the filter clamp.
the constant swelling and contracting of that hose at 50 PSI can cause a standard worm clamp to loosen creating a 50 PSI fuel spray directed at the underside of the flywheel.
NOT GOOD.

[jklevin2000]

Thanks for the reply, Can you get an OE service/repair manual, or am I stuck w/ an aftermarket one?

[rodbolt17]

any yamaha dealership can order the manual. I think you can actually order it from this site.
boats.net does parts. I am a technician that also happens to be the parts guy at work.
I am the only one that will admit he can use the computer.
I just dont like parts

[jklevin2000]

Is there anything else I should be looking for on these motors, or are they pretty straightforward? I'm an auto tech by trade and fully understand how important maintenance is to reliability.

[rodbolt17]

yes
they DO NOT tolerate poor,old or stale fuel.
they will pop a piston.
they DO NOT tolerate any fuel or cooling system degradation.
you aint even thought of maint on the auto side.
trust me I started out on that side.
the carbon issue is stupid.
personnally on the 75-100 power heads on the Z250 and Z300's I have replaced, not one had carbon issues.
they will foul plugs if idled long periods of time.
typically replace them about every 75 hours or so if *****ing a lot.
but its not a carbon foul.
its a black laqeur looking deposit that accumulates on the center electrode and porcelian.
once that black paint looking deposit makes the plug shell the arc will travel down the porcelian and not acrossed the gap.
can be easily detected with a simple Kv tester.
fireing correctly the Z300 takes 10-13 KV to fire, plug with that black stuff will show about 2-3 KV,plug that is dead(resistor opened) or the plug cap failed will show 12-18 KV.
but I have never seen one with carbon stuck rings or excessive carbon in the exhaust.
you may also wish to look at the water intrusion kit, make sure thats been done.
regulator,and a few other hulls, had live well issues that at high speeds tended to soak the motors with salt spray, just before the engine failed.
there is a tech bulliten on that as well.

[jklevin2000]

What is the water intrusion kit?

[99yam40]

Not real sure, but from what Rod wrote it sounds like it protects the motor from injesting salt water that is splashing out of the live well while at running speed

[rodbolt17]

thats exactly what it does, its also why there is a test procedure to see if it needs it.
there is a technical bulliten on that.

[jklevin2000]

Is there somewhere a non-yamaha tech can go to check out all of the tech bulletins?

[seahorse5]

Is there somewhere a non-yamaha tech can go to check out all of the tech bulletins?

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